Investigation of Spectral Effects on Photovoltaic Technologies by Modelling the Solar Spectral Distribution

Abstract

This research investigated spectral effects of four photovoltaic (PV) technologies at four locations; Alice Springs (Australia), Beijing (China), Freiburg (Germany) and Padang (Indonesia). To analyse the spectral effects, simulation tools based on the SMARTS295 clear sky model and various solar engineering equations (sun position, clearness factor, etc.) were developed. The spectral effects of all locations were analysed by taking into account the atmospheric parameters Aerosol Optical Depth (AOD), Precipitable Water Vapour (PWV) and Ozone. Spectral effects found by modelling greatly diverged for the four locations. It is therefore concluded, that these effects depend strongly on the particular location, mainly due to different distributions of absolute air mass and concentrations of aerosols. The spectral effects at the location Freiburg were modelled as well, using locally obtained parameters for a period of eight years. For a six month period, the modelled and measured spectra were compared. This comparison indicated multiple deviating results between modelled and measured data. Potential causes and involved uncertainties are discussed and recommendations addressing these differences for future research are made. Finally, for consecutive eight years the annual spectral distribution in Freiburg was modelled and related spectral effects of all four technologies were calculated. Annual spectral losses obtained ranged from year to year between -0.13 to -0.63% for a-Si; -0.27 to -0.57% for c-Si; -0.95 to -1.37% for CdTe and -0.61 to -1% for CIS.